In conventional multiple-speed bicycles, gear shift derailleurs are employed for selectively moving the drive chain laterally of the bicycle wheel over a plurality of sprockets spaced axially along the axis of the wheel. While these types of multiple speed bicycles have been satisfactory for the most part, they have been objectionable, at times, when the drive chain either does not properly engage or slips off the selected sprocket during the shifting operation.
To overcome the problems encountered in conventional derailleur-type multiple speed bicycles, the variable speed bicycle of the present invention has been devised which comprises, essentially, a variable speed pulley assembly connected between the bicycle pedal assembly and the bicycle rear axle, the movable pulley halves of the variable speed pulley assembly being actuated by cables, each cable having one end operatively connected to a respective moable pulley half and the opposite end connected to a winding drum mounted on the bicycle frame, whereby when the winding drum is turned, the cables are actuated, causing the movable pulley halves to slide laterally relative to their respective fixed pulley halves to vary the diameters of the drive and driven pulleys, to thereby change the speed of the bicycle.
By the construction and arrangement of the variable speed pulley assembly of the present invention, not only is the problem of the disconnection of the chain from the sprocket obviated, but also, more multiple speeds can be obtained than heretofore obtained in conventional three, five or ten-speed bicycles.